Catalyst compositions similar to those of the present invention are known for the oxidation of acrolein to acrylic acid. These include U.S. Pat. No. 3,725,472 which discloses the catalytic composition of molybdenum, vanadium and antimony; British Pat. No. 1,106,648 which claims a catalyst containing molybdenum, vanadium and antimony plus one of the elements of tin, nickel, chromium, and titanium; Belgium Pat. No. 763,243 which claims the combination molybdenum, vanadium, antimony plus tungsten; Belgium Pat. No. 773,851 which claims compositions containing in addition to the elements of molybdenum, vanadium, antimony and tungsten, the elements of lead, copper, tin, titanium and bismuth.